Conventionally, an information system is known in which an information center searches for a region in which a vehicle density is high on the basis of location information transmitted from vehicles, and transmits a question about a region satisfaction level to the vehicles in the found region (see, for example, PTL 1). In this information system, the information center further receives the answers for the question, and posts the information relating to the received satisfaction level on the network. The vehicles can receive the information.